1. Field of the Invention
The present invention relates generally to coin validation methods and apparatus, and in particular relates to coin validation techniques useful for a coin telephone or a similar system employing an escrow relay.
2. Description of the Prior Art
There are a variety of coin validation and authentication techniques described in the prior art.
A conventional coin telephone with coin validation means is shown schematically in FIG. 1 and referred to generally by the reference numeral 10. The coin telephone includes a housing 12, with a coin slot 14 at the upper front extremity of the housing 12, through which a coin 16 may be inserted by the customer. The coin telephone 10 includes a coin return housing 18, usually accessible via a swinging gate 20, and a coin collection box 22. (The customer return 18 and the collection box 22 are usually positioned side by side at the front of the telephone.)
The conventional telephone, as shown in FIG. 1, also includes a removable coin validator mechanism 24 and an escrow relay 26. The coin validator mechanism 24 includes two output openings 28 and 30, the first opening 28 positioned to permit a rejected coin to drop into the customer return 18, and the second opening 30 dimensioned to pass an accepted coin out of the validator 24 and into the escrow relay 26.
The coin validator 24 also typically includes a detection section 36 and coin tracks 32, 33 extending from the coin slot 14 to either of the exit openings 28 or 30. As is shown schematically in FIG. 1A, when the coin 16 passes through the coin detector 36, (note dashed line 34) if no action is taken to accept the coin, then the coin will simply pass through the exit opening 28 and into the customer return 18. On the other hand, if the coin detector 36 determines along path 34 that the coin 16 is acceptable, then a solenoid mechanism (not shown) operates an actuator gate 38, changing the path of the coin to that shown by dashed-dotted line 40, thus passing the coins through the second opening 30 and into the escrow relay 26.
If the coin 16 is in fact accepted into the escrow relay 26, the coin telephone may then either be operated by the customer, or alternatively the customer can operate a coin return mechanism (not shown) to eject the coin out of the escrow relay and into coin track 43 the customer return 18, as shown by dashed line path 42. On the other hand, if the coin telephone 10 is in fact utilized by the customer to make a call, then the escrow relay 26 deposits the coin 16 into the coin collection box 22, as shown by dotted line 44.
There are two difficulties with the above-described coin handling system in prior art coin telephones. First, such coin detectors frequently encounter difficulties with the electro mechanical actuator gate 38, which may become jammed or which may fail to operate, and therefore deter the efficient operation of the entire coin telephone. Second, a new class of public and coin telephones utilizes only the loop current along the tip and ring conductors from the telephone central office for powering all of the telephone functions. See, for example, U.S. Pat. Nos. 4,759,054 and 4,759,050. These so called "line-powered" coin telephones generate sufficient power to operate the escrow relay but may, under certain circumstances, be strained by the power requirements of the solenoid utilized to operate the acceptor gate 38 in prior art coin detector mechanisms.